16 results on '"Arun K. Mishra"'
Search Results
2. Records of the globally threatened Rusty-spotted cat in Odisha, India
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Himanshu S. Palei, Nimain C. Palei, Bhakta P. Rath, and Arun K. Mishra
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camera traps ,conservation ,distribution range ,Prionailurus rubiginosus ,small cats ,threats ,Geography. Anthropology. Recreation - Abstract
The Rusty-spotted Cat, Prionailurus rubiginosus, is a vulnerable species, endemic to India, Nepal and Sri Lanka. The goal of the study is to provide an overview of the current distribution of the Rusty-spotted Cat in Odisha state through camera trap survey, review of published scientific literature and rescue records. This study presents 14 localities including seven new localities from the Odisha state in India. A long-term study, habitat protection and studying its ecology are recommended for initiating further steps to conserve its range.
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- 2019
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3. The Combined Use of in Silico, in Vitro, and in Vivo Analyses to Assess Anti-cancerous Potential of a Bioactive Compound from Cyanobacterium Nostoc sp. MGL001
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Niveshika, Ekta Verma, Shashank K. Maurya, Rajnikant Mishra, and Arun K. Mishra
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EMTAHDCA ,anticancer drug potential ,in silico ,in vivo ,in vitro analysis ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Escalating incidences of cancer, especially in developed and developing countries, demand evaluation of potential unexplored natural drug resources. Here, anticancer potential of 9-Ethyliminomethyl-12-(morpholin-4-ylmethoxy)-5,8,13,16-tetraaza -hexacene-2,3-dicarboxylic acid (EMTAHDCA) isolated from fresh water cyanobacterium Nostoc sp. MGL001 was screened through in silico, in vitro, and in vivo studies. For in silico analysis, EMTAHDCA was selected as ligand and 11 cancer related proteins (Protein Data Bank ID: 1BIX, 1NOW, 1TE6, 2RCW, 2UVL, 2VCJ, 3CRY, 3HQU, 3NMQ, 5P21, and 4B7P) which are common targets of various anticancer drugs were selected as receptors. The results obtained from in silico analysis showed that EMTAHDCA has strong binding affinity for all the 11 target protein receptors. The ability of EMTAHDCA to bind active sites of cancer protein targets indicated that it is functionally similar to commercially available anticancer drugs. For assessing cellular metabolic activities, in vitro studies were performed by using calorimetric assay viz. 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT). Results showed that EMTAHDCA induced significant cytotoxic response against Dalton's lymphoma ascites (DLA) cells in a dose and time dependent manner with an inhibitory concentration (IC50) value of 372.4 ng/mL after 24 h of incubation. However, in case of normal bone marrow cells, the EMTAHDCA did not induce cytotoxicity as the IC50 value was not obtained even with higher dose of 1,000 ng/mL EMTAHDCA. Further, in vivo studies revealed that the median life span/survival days of tumor bearing mice treated with EMTAHDCA increased significantly with a fold change of ~1.9 and 1.81 corresponding to doses of 5 and 10 mg/kg body weight (B.W.) of EMTAHDCA respectively, as compared to the DL group. Our results suggest that 5 mg/kg B.W. is effective since the dose of 10 mg/kg B.W. did not show any significant difference as compared to 5 mg/kg B.W. Taken together, our findings based on in silico, in vitro, and in vivo analyses suggest that EMTAHDCA has potential anticancer effects, and thus, can be considered for cancer treatment.
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- 2017
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4. Active Components Based on Dynamic Negatrons
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Pavlo Molchanov, Arun K. Mishra, Helen Linnik, and Pavlo Mulyar
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Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
The active elements based on dynamic transistor negatrons (circuits with negative active differential resistance) are introduced. The principles of dynamic transistor negatrons simulation has been developed on the basis of non-linear charge model. Parameters, which characterize non-linear mode of dynamic transistor negatrons, are derived. Nonlinear equivalent circuit and Volterra series are used to calculate parameters of negatrons. Particular attention is devoted to the frequency mixers and frequency switches. An experimental frequency mixer has been described, that has confirms the theoretical predictions.
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- 2000
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5. Synthesis and antimicrobial activity of some new diphenylamine derivatives
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Arun K. Mishra and Arvind Kumar
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lcsh:QD71-142 ,diphenylamine ,Short Communication ,Hydrazine ,Diphenylamine ,aromatic aldehydes ,lcsh:Analytical chemistry ,chemistry.chemical_element ,lcsh:RS1-441 ,Bioengineering ,Antimicrobial activity ,Antimicrobial ,General Biochemistry, Genetics and Molecular Biology ,lcsh:Pharmacy and materia medica ,chemistry.chemical_compound ,Acetic acid ,chemistry ,Chlorine ,Methanol ,General Pharmacology, Toxicology and Pharmaceutics ,Hydrate ,chloroacetylation ,Acetamide ,Nuclear chemistry - Abstract
In search of new leads toward potent antimicrobial agent, an array of novel derivatives of 2-hydrazinyl -N-N, diphenyl acetamide has been synthesized from the chloroacetylation reaction of diphenylamine (DPA). For this, a series of DPA derivatives were prepared by replacing chlorine with hydrazine hydrate in alcoholic medium and 2-hydrazino-N, N-diphenylacetamide was synthesized. The 2-hydrazino-N, N-diphenylacetamide was further subjected to reaction with various aromatic aldehydes in presence of glacial acetic acid in methanol. The synthesized compounds were characterized by their IR, 1HNMR spectral data and elemental analysis. The compounds were screened for antibacterial and antifungal activity by cup plate method. 2-(2-Benzylidenehydrazinyl)-N, N-diphenylacetamide (A1); 2-(2-(3-methylbenzylidene) hydrazinyl)-N, N-diphenyl-acetamide (A5) and 2-(2-(2-nitrobenzylidine) hydrazinyl)-N, N-diphenyl-acetamide compounds (A7) showed significant antimicrobial as well as antifungal activity. Diphenylamine compounds may be explored as potent antimicrobial and antifungal compounds.
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- 2015
6. Oleandrin: A cardiac glycosides with potent cytotoxicity
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Tanmoy De, Arun K. Mishra, Amrita Mishra, and Arvind Kumar
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Pharmacology ,Programmed cell death ,Oleandrin ,Cardiac glycosides ,Notice of Retraction ,oleandrin ,Plant Science ,Review Article ,Biology ,medicine.disease_cause ,chemistry.chemical_compound ,Complementary and alternative medicine ,chemistry ,Cell culture ,Apoptosis ,Drug Discovery ,medicine ,Cytotoxic T cell ,cytotoxicity ,Cytotoxicity ,Carcinogenesis ,Cardiac glycoside ,medicine.drug - Abstract
Cardiac glycosides are used in the treatment of congestive heart failure and arrhythmia. Current trend shows use of some cardiac glycosides in the treatment of proliferative diseases, which includes cancer. Nerium oleander L. is an important Chinese folk medicine having well proven cardio protective and cytotoxic effect. Oleandrin (a toxic cardiac glycoside of N. oleander L.) inhibits the activity of nuclear factor kappa-light-chain-enhancer of activated B chain (NF-κB) in various cultured cell lines (U937, CaOV3, human epithelial cells and T cells) as well as it induces programmed cell death in PC3 cell line culture. The mechanism of action includes improved cellular export of fibroblast growth factor-2, induction of apoptosis through Fas gene expression in tumor cells, formation of superoxide radicals that cause tumor cell injury through mitochondrial disruption, inhibition of interleukin-8 that mediates tumorigenesis and induction of tumor cell autophagy. The present review focuses the applicability of oleandrin in cancer treatment and concerned future perspective in the area.
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- 2013
7. Identification of a novel α(1→6) mannopyranosyltransferase MptB from Corynebacterium glutamicum by deletion of a conserved gene, NCgl1505, affords a lipomannan- and lipoarabinomannan-deficient mutant
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Apoorva Bhatt, Gurdyal S. Besra, Arun K. Mishra, Doris Rittmann, Kuni Takayama, Lothar Eggeling, Luke J. Alderwick, William R. Jacobs, and Cindy Wang
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Lipopolysaccharides ,Mycobacterium smegmatis ,medicine.disease_cause ,Microbiology ,Mannosyltransferases ,Corynebacterium glutamicum ,Mycobacterium tuberculosis ,03 medical and health sciences ,Bacterial Proteins ,Glycosyltransferase ,medicine ,Molecular Biology ,Research Articles ,030304 developmental biology ,chemistry.chemical_classification ,0303 health sciences ,Mutation ,Lipomannan ,Lipoarabinomannan ,biology ,030306 microbiology ,Genetic Complementation Test ,Gene Expression Regulation, Bacterial ,biology.organism_classification ,Molecular biology ,3. Good health ,Biosynthetic Pathways ,Enzyme ,chemistry ,biology.protein ,Gene Deletion ,Genome, Bacterial - Abstract
Mycobacterium tuberculosis and Corynebacterium glutamicum share a similar cell wall structure and orthologous enzymes involved in cell wall assembly. Herein, we have studied C. glutamicum NCgl1505, the orthologue of putative glycosyltransferases Rv1459c from M. tuberculosis and MSMEG3120 from Mycobacterium smegmatis. Deletion of NCgl1505 resulted in the absence of lipomannan (Cg-LM-A), lipoarabinomannan (Cg-LAM) and a multi-mannosylated polymer (Cg-LM-B) based on a 1,2-di-O-C(16)/C(18:1)-(alpha-D-glucopyranosyluronic acid)-(1--3)-glycerol (GlcAGroAc(2)) anchor, while syntheses of triacylated-phosphatidyl-myo-inositol dimannoside (Ac(1)PIM(2)) and Man(1)GlcAGroAc(2) were still abundant in whole cells. Cell-free incubation of C. glutamicum membranes with GDP-[(14)C]Man established that C. glutamicum synthesized a novel alpha(1--6)-linked linear form of Cg-LM-A and Cg-LM-B from Ac(1)PIM(2) and Man(1)GlcAGroAc(2) respectively. Furthermore, deletion of NCgl1505 also led to the absence of in vitro synthesized linear Cg-LM-A and Cg-LM-B, demonstrating that NCgl1505 was involved in core alpha(1--6) mannan biosynthesis of Cg-LM-A and Cg-LM-B, extending Ac(1)PI[(14)C]M(2) and [(14)C]Man(1)GlcAGroAc(2) primers respectively. Use of the acceptor alpha-D-Manp-(1--6)-alpha-D-Manp-O-C(8) in an in vitro cell-free assay confirmed NCgl1505 as an alpha(1--6) mannopyranosyltransferase, now termed MptB. While Rv1459c and MSMEG3120 demonstrated similar in vitroalpha(1--6) mannopyranosyltransferase activity, deletion of the Rv1459c homologue in M. smegmatis did not result in loss of mycobacterial LM/LAM, indicating a functional redundancy for this enzyme in mycobacteria.
- Published
- 2008
8. Benzothiazinones Mediate Killing of Corynebacterineae by Blocking Decaprenyl Phosphate Recycling Involved in Cell Wall Biosynthesis
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Shipra, Grover, Luke J, Alderwick, Arun K, Mishra, Karin, Krumbach, Jan, Marienhagen, Lothar, Eggeling, Apoorva, Bhatt, and Gurdyal S, Besra
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Thiazines ,Drug Resistance ,Glycobiology and Extracellular Matrices ,Bacterial Metabolism ,Mycobacterium tuberculosis ,Corynebacterium glutamicum ,Alcohol Oxidoreductases ,Bacterial Proteins ,Polyisoprenyl Phosphates ,Cell Wall ,ddc:570 ,Carbohydrate Metabolism ,bacteria ,Spiro Compounds ,Enzyme Inhibitors ,Oxidoreductases ,Polysaccharide - Abstract
Background: Benzothiazinones inhibit cell wall arabinan biosynthesis, which is lethal for Corynebacterineae. Results: Corynebacteria can evade the action of benzothiazinones in the absence of decaprenyl phosphoribose synthesis by increasing the intracellular decaprenyl phosphate pool. Conclusion: Benzothiazinones induce synthetic lethality in Corynebacterineae by blocking decaprenyl phosphate recycling. Significance: Increased production of decaprenyl phosphate is a new mechanism of resistance to benzothiazinones., Benzothiazinones (BTZs) are a new class of sulfur containing heterocyclic compounds that target DprE1, an oxidoreductase involved in the epimerization of decaprenyl-phosphoribose (DPR) to decaprenyl-phosphoarabinose (DPA) in the Corynebacterineae, such as Corynebacterium glutamicum and Mycobacterium tuberculosis. As a result, BTZ inhibition leads to inhibition of cell wall arabinan biosynthesis. Previous studies have demonstrated the essentiality of dprE1. In contrast, Cg-UbiA a ribosyltransferase, which catalyzes the first step of DPR biosynthesis prior to DprE1, when genetically disrupted, produced a viable mutant, suggesting that although BTZ biochemically targets DprE1, killing also occurs through chemical synthetic lethality, presumably through the lack of decaprenyl phosphate recycling. To test this hypothesis, a derivative of BTZ, BTZ043, was examined in detail against C. glutamicum and C. glutamicum::ubiA. The wild type strain was sensitive to BTZ043; however, C. glutamicum::ubiA was found to be resistant, despite possessing a functional DprE1. When the gene encoding C. glutamicum Z-decaprenyl-diphosphate synthase (NCgl2203) was overexpressed in wild type C. glutamicum, resistance to BTZ043 was further increased. This data demonstrates that in the presence of BTZ, the bacilli accumulate DPR and fail to recycle decaprenyl phosphate, which results in the depletion of decaprenyl phosphate and ultimately leads to cell death.
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- 2014
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9. Differential arabinan capping of lipoarabinomannan modulates innate immune responses and impacts T helper cell differentiation
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Karin Krumbach, Lothar Eggeling, Gurdyal S. Besra, Margarida Saraiva, Jérôme Nigou, António G. Castro, Joana Alves, Jeroen Geurtsen, Arun K. Mishra, Medical Microbiology and Infection Prevention, CCA - Immuno-pathogenesis, and Universidade do Minho
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Lipopolysaccharides ,animal diseases ,Biochemistry ,Dendritic cells ,Mice ,0302 clinical medicine ,Receptor ,Cells, Cultured ,0303 health sciences ,Mice, Inbred BALB C ,Pattern recognition receptor ,Cell Differentiation ,3. Good health ,medicine.anatomical_structure ,Female ,T cell ,Immunology ,T Cell ,chemical and pharmacologic phenomena ,Toll-like receptors (TLR) ,Biology ,Microbiology ,03 medical and health sciences ,Immune system ,Polysaccharides ,medicine ,Animals ,Humans ,Molecular Biology ,Cytokine ,030304 developmental biology ,Innate immune system ,Lipoarabinomannan ,Lipomannan ,Science & Technology ,Corynebacterium Infections ,Glycosyltransferases ,Cell Biology ,Dendritic Cells ,biochemical phenomena, metabolism, and nutrition ,Immunity, Innate ,Corynebacterium glutamicum ,Mice, Inbred C57BL ,TLR2 ,HEK293 Cells ,Toll-like Receptors (TLR) ,bacteria ,Th17 Cells ,030215 immunology - Abstract
We acknowledge scientific discussions with Drs. Anne O'Garra, Luke Alderwick, and Apoorva Bhatt., Background: Lipoglycans modulate the initiation of immune responses by interacting with TLR2. Results: A hypermannosylated lipomannan variant, once recognized by the immune system, enhance both innate responses and Th17 differentiation. Conclusion: Altered lipoglycan structures are differently recognised by innate immune cells with an impact on the adaptive immune response. Significance: Specific lipoglycan structures may be useful to modulate immune responses. Resume: Toll-like receptors (TLRs) recognize pathogens by interacting with pathogen-associated molecular patterns, such as the phosphatidylinositol-based lipoglycans, lipomannan (LM) and lipoarabinomannan (LAM). Such structures are present in several pathogens, including Mycobacterium tuberculosis, being important for the initiation of immune responses. It is well established that the interaction of LM and LAM with TLR2 is a process dependent on the structure of the ligands. However, the implications of structural variations on TLR2 ligands for the development of T helper (Th) cell responses or in the context of in vivo responses are less studied. Herein, we used Corynebacterium glutamicum as a source of lipoglycan intermediates for host interaction studies. In this study, we have deleted a putative glycosyltransferase, NCgl2096, from C. glutamicum and found that it encodes for a novel α(1→2)arabinofuranosyltransferase, AftE. Biochemical analysis of the lipoglycans obtained in the presence (wild type) or absence of NCgl2096 showed that AftE is involved in the biosynthesis of singular arabinans of LAM. In its absence, the resulting molecule is a hypermannosylated (hLM) form of LAM. Both LAM and hLM were recognized by dendritic cells, mainly via TLR2, and triggered the production of several cytokines. hLM was a stronger stimulus for in vitro cytokine production and, as a result, a more potent inducer of Th17 responses. In vivo data confirmed hLM as a stronger inducer of cytokine responses and suggested the involvement of pattern recognition receptors other than TLR2 as sensors for lipoglycans., Margarida Saraiva Supported by Fundação para a Ciência e Tecnologia (FCT), Portugal, Personal Grant PTDC/SAU-MII/101977/2008; Gurdyal S. Besra Supported by a Personal Research Chair from James Bardrick, a Royal Society Wolfson Research Merit Award, a Lister Institute-Jenner research fellowship, the Medical Research Council, and Wellcome Trust Grant 081569/Z/06/Z. António G. Castro Supported by FCT, Portugal, Project Grant PTDC/SAU-MII/101977/2008. Jeroen Geurtsen Supported by the Netherlands Organization for Scientific Research (NWO) through a VENI research grant (016.101.001).
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- 2012
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10. Acceptor Substrate Discrimination in Phosphatidyl-myo-inositol Mannoside Synthesis
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Gurdyal S. Besra, Lothar Eggeling, Klaus Fütterer, Arun K. Mishra, Natacha Veerapen, Karin Krumbach, Sarah M. Batt, and Talat Jabeen
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chemistry.chemical_classification ,0303 health sciences ,Mannosyltransferase ,QP Physiology ,Lipomannan ,biology ,Stereochemistry ,Glycoconjugate ,030302 biochemistry & molecular biology ,Cell Biology ,Biochemistry ,Corynebacterium glutamicum ,03 medical and health sciences ,chemistry.chemical_compound ,Protein structure ,chemistry ,Glycosyltransferase ,biology.protein ,Inositol ,Glycosyl ,Molecular Biology ,030304 developmental biology - Abstract
Long term survival of the pathogen Mycobacterium tuberculosis in humans is linked to the immunomodulatory potential of its complex cell wall glycolipids, which include the phosphatidylinositol mannoside (PIM) series as well as the related lipomannan and lipoarabinomannan glycoconjugates. PIM biosynthesis is initiated by a set of cytosolic α-mannosyltransferases, catalyzing glycosyl transfer from the activated saccharide donor GDP-α-d-mannopyranose to the acceptor phosphatidyl-myo-inositol (PI) in an ordered and regio-specific fashion. Herein, we report the crystal structure of mannosyltransferase Corynebacterium glutamicum PimB′ in complex with nucleotide to a resolution of 2.0 Å. PimB′ attaches mannosyl selectively to the 6-OH of the inositol moiety of PI. Two crystal forms and GDP- versus GDP-α-d-mannopyranose-bound complexes reveal flexibility of the nucleotide conformation as well as of the structural framework of the active site. Structural comparison, docking of the saccharide acceptor, and site-directed mutagenesis pin regio-selectivity to a conserved Asp residue in the N-terminal domain that forces presentation of the correct inositol hydroxyl to the saccharide donor.
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- 2010
11. Structural characterization of a partially arabinosylated lipoarabinomannan variant isolated from a Corynebacterium glutamicum ubiA mutant
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Jérôme Nigou, Lothar Eggeling, Martine Gilleron, Assunta Giordano, Howard R. Morris, Gurdyal S. Besra, Anne Dell, Arun K. Mishra, Raju V. V. Tatituri, Karin Krumbach, Luke J. Alderwick, Paul G. Hitchen, Defence Institute of Advanced Technology, Institut de pharmacologie et de biologie structurale (IPBS), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Clinical Research Center, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Huddinge, Sweden, and Karolinska Institutet [Stockholm]-Karolinska University Hospital [Stockholm]
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Lipopolysaccharides ,Models, Molecular ,Carbohydrates ,Prenyltransferase activity ,Microbiology ,Corynebacterium glutamicum ,03 medical and health sciences ,chemistry.chemical_compound ,immune system diseases ,Arabinogalactan ,hemic and lymphatic diseases ,Glycosyl ,[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM] ,ComputingMilieux_MISCELLANEOUS ,030304 developmental biology ,Mannan ,0303 health sciences ,Phosphotransferases (Phosphate Group Acceptor) ,Lipoarabinomannan ,Molecular mass ,Chemistry ,030302 biochemistry & molecular biology ,Biochemistry and Molecular Biology ,bacterial infections and mycoses ,3. Good health ,Molecular Weight ,Biochemistry ,Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ,Mutation ,lipids (amino acids, peptides, and proteins) ,ARAF ,Metabolic Networks and Pathways - Abstract
Arabinan polysaccharide side-chains are present in both Mycobacterium tuberculosis and Corynebacterium glutamicum in the heteropolysaccharide arabinogalactan (AG), and in M. tuberculosis in the lipoglycan lipoarabinomannan (LAM). This study shows by quantitative sugar and glycosyl linkage analysis that C. glutamicum possesses a much smaller LAM version, Cg-LAM, characterized by single t-Araf residues linked to the alpha(1--6)-linked mannan backbone. MALDI-TOF MS showed an average molecular mass of 13,800-15 400 Da for Cg-LAM. The biosynthetic origin of Araf residues found in the extracytoplasmic arabinan domain of AG and LAM is well known to be provided by decaprenyl-monophosphoryl-D-arabinose (DPA). However, the characterization of LAM in a C. glutamicum : : ubiA mutant devoid of prenyltransferase activity and devoid of DPA-dependent arabinan deposition into AG revealed partial formation of LAM, albeit with a slightly altered molecular mass. These data suggest that in addition to DPA utilization as an Araf donor, alternative pathways exist in Corynebacterianeae for Araf delivery, possibly via an unknown sugar nucleotide.
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- 2007
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12. MSX-resistant mutants of Anabaena 7120 with derepressed heterocyst development and nitrogen fixation.
- Author
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Arun K. Mishra
- Abstract
To investigate the role of ammonium-assimilating enzyme in heterocyst differentiation, pattern formation and nitrogen fixation, MSX-resistant and GS-impaired mutants of Anabaena 7120 were isolated using transposon (Tn5-1063) mutagenesis. Mutant Gs1 and Gs2 (impaired in GS activity) exhibited a similar rate of nitrogenase activity compared to that of the wild type under dinitrogen aerobic conditions in the presence and absence of MSX. Filaments of Gs1 and Gs2 produced heterocysts with an evenly spaced pattern in N
2 -grown conditions, while addition of MSX altered the interheterocyst spacing pattern in wild type as well as in mutant strains. The wild type showed complete repression of heterocyst development and nitrogen fixation in the presence of NO3 − or NH4 + , whereas the mutants Gs1 and Gs2 formed heterocysts and fixed nitrogen in the presence of NO3 − and NH4 + . Addition of MSX caused complete inhibition of glutamine synthetase activity in wild type but Gs1 and Gs2 remained unaffected. These results suggest that glutamine but not ammonium is directly involved in regulation of heterocyst differentiation, interheterocyst spacing pattern and nitrogen fixation in Anabaena. [ABSTRACT FROM AUTHOR]- Published
- 2003
13. Synthesis and antimicrobial activity of some new diphenylamine derivatives
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Arvind Kumar and Arun K Mishra
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Antimicrobial activity ,aromatic aldehydes ,chloroacetylation ,diphenylamine ,Pharmacy and materia medica ,RS1-441 ,Analytical chemistry ,QD71-142 - Abstract
In search of new leads toward potent antimicrobial agent, an array of novel derivatives of 2-hydrazinyl -N-N, diphenyl acetamide has been synthesized from the chloroacetylation reaction of diphenylamine (DPA). For this, a series of DPA derivatives were prepared by replacing chlorine with hydrazine hydrate in alcoholic medium and 2-hydrazino-N, N-diphenylacetamide was synthesized. The 2-hydrazino-N, N-diphenylacetamide was further subjected to reaction with various aromatic aldehydes in presence of glacial acetic acid in methanol. The synthesized compounds were characterized by their IR, 1HNMR spectral data and elemental analysis. The compounds were screened for antibacterial and antifungal activity by cup plate method. 2-(2-Benzylidenehydrazinyl)-N, N-diphenylacetamide (A1); 2-(2-(3-methylbenzylidene) hydrazinyl)-N, N-diphenyl-acetamide (A5) and 2-(2-(2-nitrobenzylidine) hydrazinyl)-N, N-diphenyl-acetamide compounds (A7) showed significant antimicrobial as well as antifungal activity. Diphenylamine compounds may be explored as potent antimicrobial and antifungal compounds.
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- 2015
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14. A simple Ultraviolet spectrophotometric method for the determination of etoricoxib in dosage formulations
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Shipra Singh, Amrita Mishra, Anurag Verma, Ashoke K Ghosh, and Arun K Mishra
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Etoricoxib ,quality control ,UV spectrometry ,validation ,Therapeutics. Pharmacology ,RM1-950 ,Pharmacy and materia medica ,RS1-441 - Abstract
The present study was undertaken to develop a validated, rapid, simple, and low-cost ultraviolet (UV) spectrophotometric method for estimating Etoricoxib (ETX) in pharmaceutical formulations. The analysis was performed on λ max 233 nm using 0.1 M HCl as blank/diluent. The proposed method was validated on International Conference on Harmonization (ICH) guidelines including parameters as linearity, accuracy, precision, reproducibility, and specificity. The proposed method was also used to access the content of the ETX in two commercial brands of Indian market. Beer′s law was obeyed in concentration range of 0.1-0.5 μg/ml, and the regression equation was Y = 0.418x + 0.018. The mean accuracy values for 0.1 μg/ml and 0.2 μg/ml concentration of ETX were found to be 99.76 ± 0.52% and 99.12 ± 0.84, respectively, and relative standard deviation (RSD) of interday and intraday was less than 2%. The developed method was suitable and specific to the analysis of ETX even in the presence of common excipients. The method was applied on two different marketed brands and ETX contents were 98.5 ± 0.56 and 99.33 ± 0.44, respectively, of labeled claim. The proposed method was validated as per ICH guidelines and statistically good results were obtained. This method can be employed for routine analysis of ETX in bulk and commercial formulations.
- Published
- 2012
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15. A simple Ultraviolet spectrophotometric method for the determination of etoricoxib in dosage formulations.
- Author
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S Singh, A Mishra, A Verma, Ashoke K Ghosh, and Arun K Mishra
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Therapeutics. Pharmacology ,RM1-950 ,Pharmacy and materia medica ,RS1-441 - Abstract
The present study was undertaken to develop a validated, rapid, simple, and low-cost ultraviolet (UV) spectrophotometric method for estimating Etoricoxib (ETX) in pharmaceutical formulations. The analysis was performed on Î max 233 nm using 0.1 M HCl as blank/diluent. The proposed method was validated on International Conference on Harmonization (ICH) guidelines including parameters as linearity, accuracy, precision, reproducibility, and specificity. The proposed method was also used to access the content of the ETX in two commercial brands of Indian market. Beer′s law was obeyed in concentration range of 0.1-0.5 μg/ml, and the regression equation was Y = 0.418x + 0.018. The mean accuracy values for 0.1 μg/ml and 0.2 μg/ml concentration of ETX were found to be 99.76 ± 0.52% and 99.12 ± 0.84, respectively, and relative standard deviation (RSD) of interday and intraday was less than 2%. The developed method was suitable and specific to the analysis of ETX even in the presence of common excipients. The method was applied on two different marketed brands and ETX contents were 98.5 ± 0.56 and 99.33 ± 0.44, respectively, of labeled claim. The proposed method was validated as per ICH guidelines and statistically good results were obtained. This method can be employed for routine analysis of ETX in bulk and commercial formulations.
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- 2012
- Full Text
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16. Gram-positive bacterial lipoglycans based on a glycosylated diacylglycerol lipid anchor are microbe-associated molecular patterns recognized by TLR2.
- Author
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Landry Blanc, Romain Castanier, Arun K Mishra, Aurélie Ray, Gurdyal S Besra, Iain Sutcliffe, Alain Vercellone, and Jérôme Nigou
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Medicine ,Science - Abstract
Innate immune recognition is the first line of host defense against invading microorganisms. It is a based on the detection, by pattern recognition receptors (PRRs), of invariant molecular signatures that are unique to microorganisms. TLR2 is a PRR that plays a major role in the detection of Gram-positive bacteria by recognizing cell envelope lipid-linked polymers, also called macroamphiphiles, such as lipoproteins, lipoteichoic acids and mycobacterial lipoglycans. These microbe-associated molecular patterns (MAMPs) display a structure based on a lipid anchor, being either an acylated cysteine, a glycosylated diacylglycerol or a mannosyl-phosphatidylinositol respectively, and having in common a diacylglyceryl moiety. A fourth class of macroamphiphile, namely lipoglycans, whose lipid anchor is made, as for lipoteichoic acids, of a glycosylated diacylglycerol unit rather than a mannosyl-phosphatidylinositol, is found in Gram-positive bacteria and produced by certain Actinobacteria, including Micrococcus luteus, Stomatococcus mucilaginosus and Corynebacterium glutamicum. We report here that these alternative lipoglycans are also recognized by TLR2 and that they stimulate TLR2-dependant cytokine production, including IL-8, TNF-α and IL-6, and cell surface co-stimulatory molecule CD40 expression by a human macrophage cell line. However, they differ by their co-receptor requirement and the magnitude of the innate immune response they elicit. M. luteus and S. mucilaginosus lipoglycans require TLR1 for recognition by TLR2 and induce stronger responses than C. glutamicum lipoglycan, sensing of which by TLR2 is dependent on TLR6. These results expand the repertoire of MAMPs recognized by TLR2 to lipoglycans based on a glycosylated diacylglycerol lipid anchor and reinforce the paradigm that macroamphiphiles based on such an anchor, including lipoteichoic acids and alternative lipoglycans, induce TLR2-dependant innate immune responses.
- Published
- 2013
- Full Text
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